Receiver dialog box
The Receiver dialog box allows you to set up the detailed parameters for the signal reception. It allows you to "fine tune" the electronic circuitry in the receiver for optimal performance in different sea conditions, and for different gear types. Each receiver must be able to accept and recognize the data from the gear monitoring sensors.
Prerequisites
The Receiver dialog box is only available when you have set up a serial line communication with a sensor receiver. This dialog box is license dependant.
How to open
This dialog box is opened from the I/O Setup page, on the Installation dialog box. The Installation dialog box is located on the Setup menu.
To open, select the sensor receiver icon in the “block diagram”.
Image
Description
The parameters provided are used to establish and maintain the quality of the communication between the sensor receiver and the individual gear monitoring sensors. The parameters have a major influence on the TV80 performance. The default settings are those we have found to be the best for general use, but for individual installations other specific settings may enhance the performance.
Image
Details
Interference Filter
The Interference Filter removes noise and false echoes from other echo sounders and sonars in the vicinity of your vessel.
The default setting of the filter is Off.
Interference Filter Level
The Interference Filter Level allows you to specify the strength of the interference filter. When the interference filter is used, you can adjust the strength to suit your preferences and the current conditions.
Sensor Filter
The Sensor Filter can be used if you have problems with the reception. It will average the data received from the sensors.
After the sensors have been submerged, the receiver requires only three consecutive pings from individual sensors to calculate and display their respective information. However, if you experience problems with the reception, you may try this filter. The default setting of the Sensor filter is Off.
The following options are available:
•  Off
The Sensor filter is switched off.
•  Weak
The information from the last four sensor transmissions are averaged.
•  Medium
The information from the last eight sensor transmissions are averaged. This has proven to be a useful setting for trawlers.
•  Strong
The information from the last 16 sensor transmissions are averaged.
Catch/Bottom Filter
The Catch/Bottom Filter is used to restrict the change of state from the catch and bottom contact sensors. This will reduce jitter in the presentation. When the filter is switched off any change in measurement status will immediately be shown in the presentation. The default setting of the filter is Weak.
The following options are available:
•  Off
The filter is switched off.
•  Weak
The information provided from the sensors must be stable for at least two consecutive transmissions. If this is not the case, the information is not shown in the TV80 presentation.
•  Medium
The information provided from the sensors must be stable for at least four consecutive transmissions. If this is not the case, the information is not shown in the TV80 presentation.
•  Strong
The information provided from the sensors must be stable for at least eight consecutive transmissions. If this is not the case, the information is not shown in the TV80 presentation.
AGC (Automatic Gain Control)
The AGC (Automatic Gain Control) function runs an automatic analysis of the echo strength. During normal operation, On  is the recommended (and default) setting.
Manual Gain
This function allows you to apply a selected amount of gain to the receiver circuitry. If you decide to switch the AGC off you must set the gain manually.
The default and recommended setting is Medium.
Multipath Filter
The Multipath Filter is designed to remedy for reflections, spikes and time-lag in the sensor data. These problems may occur if neighbouring channels are used, or if the TV80 system is disturbed by other hydroacoustic systems in use on your own or other vessels.
When you operate in areas with substantial reverberation due to the bottom conditions, or in shallow waters, you may experience “jumps” or spikes in the data received from the sensors. Such errors can also be caused by other types of hydroacoustic equipment operating on the same freqyency range as the TV80 system. The Multipath Filter has also been implemented to remedy for such interference problems.
Note
We recommend that you switch this filter On if there are large fluctuations in the displayed data, or if the rate of change is small. If instantaneous readings are required, do not activate the filter. This shortens the delay between updating the changes in sensor data, and the corresponding displayed information.
Water Profile
Use these settings to set up the TV80 system for operation in fresh or salt water.
Detection Threshold (DT)
This parameter is used to control the threshold level for detection of signals. Signals below the threshold level will not be detected, while signals above the threshold will be detected. Setting the threshold level too low may cause false signals to be detected. If the detection threshold is set too high, the signal from the gear monitoring sensor will not be detected.
For the TV80 system, two different parameter ranges are used.
•  3 to 14
By increasing the parameter value, the threshold level is increased.
•  15 to 20
By increasing the parameter value, the threshold level is decreased.
The default value for Detection Threshold (DT) is 17.
Max shooting speed
The TV80 has a built-in Doppler compensation function which is set up using this parameter. The parameter and related function is, however, only relevant if sensor data is desired while the purse seine or trawl is being deployed. It has no effect once the vessel is stopped and waiting for the net or trawl to sink.
Note
If you set this parameter too high, you may create a conflict with the channel selection.